Substrates for cleaning and filtering pollutants and particulates on surfaces and in the air are known in the art. Pollutants such as odors (e.g. cigarette smoke), volatile organixc compounds (“VOCs”), microbials (e.g. bacteria, viruses, mold), and particulates (e.g. dust) have a pernicious effect when inhaled or otherwise contacted by human beings. Particulates alone comprise dead skin, pet dander, dust mite feces, and other microscopic (less than 5 microns in size) particulates which may elicit a human immune response.
In addition to particulate cleaning efficiency, consumers may desire filter substrates that provide low pressure drop as air passes through the substrate because this can provide low noise levels. Low noise levels may be attractive to consumers to enable long air filtering operations times (e.g. operating 24 hours a day). Various attempts in the art have been made to provide consumer affordable filter substrates with improved cleaning efficiency and minimal noise. However, improvements on noise and cleaning efficiency typically compromise a manufacturer's ability to produce low cost filter substrates and/or negatively affects another consumer desired aspect of a filter substrate.
Accordingly, there continues to be a need for an improved filter substrate for an air filtering device which cost-effectively, and with improved efficiency, removes particulates from the air while having consumer-friendly features such as compactness/portability and consumer acceptable noise levels.